The present invention relates to a belt unit installed apparatus, an image forming apparatus having the belt unit installed apparatus, and a method of installing/removing a belt unit.
As an example of a belt unit installed apparatus, in which a belt unit is installed, there is provided an image forming apparatus of electronic-photography type such as a printer, a copier, a facsimile, and a multifunction device.
In a conventional image forming apparatus such as a color printer, an image is formed through the following process. First, a charge roller charges a surface of a photosensitive drum. An exposure device such as an LED head exposes the surface of the photosensitive drum to form a static latent image or a latent image thereon. A developing roller attaches a thin layer of toner to the static latent image to form a toner image. A transfer roller transfers the toner image to a sheet. A fixing device fixes the toner image to the sheet, and the sheet is discharged. A cleaning blade scrapes off toner remaining on the photosensitive drum after the transfer roller transfers the toner image.
In the conventional image forming apparatus, the photosensitive drum, the charge roller, the developing roller, and the cleaning blade are combined in an image forming unit (ID unit or developing device). The image forming unit is disposed per color such as black, yellow, magenta, and cyan. A belt unit for transfer is disposed to face the photosensitive drum of each of the image forming units.
The belt unit is formed of a drive roller; a follower roller; a transfer belt placed between the drive roller and the follower roller to be freely movable; a transfer roller facing the photosensitive drum through the transfer belt; and the likes. The belt unit is detachably attached to the image forming apparatus, so that it is possible to easily perform maintenance, inspection, exchange, and the likes (refer to Patent Reference).
FIG. 2 is a schematic perspective view showing an attachment portion of a conventional belt unit. As shown in FIG. 2, the belt unit is attached to a frame 26 disposed on a main body of a printer or an apparatus main body. A bearing receiving portion 27 is disposed in the frame 26 at a specific position thereof. The belt unit has a bearing for supporting a drive roller to be freely rotatable.
When the belt unit is attached to the frame 26, the bearing engages the bearing receiving portion 27, and a gear 29 disposed on the apparatus main body engages a gear of the drive roller. A lock member 28 is disposed to be freely rotatable relative to the frame 26 for pushing the bearing from above, so that an upward movement of the bearing is restricted. A spring (not shown) urges the lock member 28 in an arrow direction A.
Patent Reference: Japanese Patent Publication No. 2002-60039
In the printer, when the belt unit is detached from the apparatus main body, the lock member 28 is moved with one hand of an operator, and the belt unit is pulled up while the other hand holds a handle attached to the belt unit. Accordingly, it is difficult to detach the belt unit from the printer.
In view of the problems described above, an object of the present invention is to provide a belt unit installed apparatus, in which it is possible to easily attach and detach a belt unit.
Further objects and advantages of the invention will be apparent from the following description of the invention.